Kyungpook National University - 3DOT3dot.knu.ac.kr/.../2015/05/Technologies-of-Digital... · 3DOT Technologies of Digital Holographic Display Joonku Hahn Kyungpook National University

3 Dimensional Optical Technology 3DOT

Technologies of Digital Holographic Display

Joonku Hahn

Kyungpook National University

http://www.knu.ac.kr/bbs/newmain/index.jsp


Outline:

1. Classification of digital holographic display

2. Data capacity, View volume and Resolution

3. Holographic stereogram vs. Stereoscopic hologram

4. Prospective applications

5. Summary

1



2


Holo Graphy




3

Modulation

Type of SLM

Spatial multiplexing

Temporal multiplexing Multiplexing

Spatial light modulator

Number of SLMs

Application

Personal display

Public display

Miscellaneous ways Data capacity, Color, Screen size,

Field of view, Parallax, Real-time,…




4

Liquid crystal display

(LCD) modulator

Digital micro-mirror device

(DMD) modulator

Spatial Light Modulator (SLM)

Acousto-optic modulator

(AOM)

Types of SLM

Liquid crystal on Silicon

(LCoS) modulator




5

Spatial Light Modulator (SLM)

Amplitude-only modulation

Phase-only modulation

-1 1

i

-i

Re

Im

Full-complex modulation

-1 1

i

-i

Re

Im

Modulations

Typical characteristic

of liquid crystal device

-1 1

i

-i

Re

Im

-1 1

i

-i

Re

Im




6

Multiplexing

Temporal multiplexing

T.-C. Poon, J. of info. Display 3, 12 (2002).

Y. Takaki and N. Okada, Appl. Opt 48, 3255 (2009).

Parallax: Horizontal parallax-only

Screen size: 150×75 mm2

Device : 18-channel AOM

Field of view: 55° (estimated)

Data capacity: 294.9Mb

http://www.media.mit.edu/spi/M2.html

Screen size: 96.9×52.5 mm2

Field of view 14.6°

Device : 1 DMD


Data capacity: 146Mb



7


Multiplexing

Temporal multiplexing

screen

laser spatial

filter

collimation

lens

DMD

with a beamsplitter

cylindrical lenses galvanometer

Our scanning holographic display system




8

Multiplexing



Field of view:22.8°

Device: 12 TNLC SLM




Field of view:24°

Device: 9 LCoS SLM

Parallax: Full parallax



Field of view:9.95°

Device: 6 LCoS SLM



J. Hahn, H. Kim, Y. Lim, G. Park, and B. Lee, Opt. Express 16, 12372 (2008).

F. Yaraş, H. Kang, and L. Onural, Opt. Express 19, 9147 (2011).

T. Kozacki, M. Kujawińska, G. Finke, W. Zaperty, and B. Hennelly, J. Display Technol. 8, 225 (2012).



2D array of SLMs

Array of transfer lenses

Surface where apertures are synthesized

9


Multiplexing




Field lens

Fourier lens

SLM

Laser

Collimator

10


Multiplexing


Our scalable holographic display system

under the co-work with Prof. Hwi Kim’s lab in Korea University




11

Multiplexing

Spatiotemporal multiplexing



Device : 4channels

(1 EASLM-25 OASLMs)

Field of view: 5.3°

Data capacity: 100Mb

Replication optics

and shutters

Optically

addressed

SLM

Electrically

addressed

– SLM

C. Slinger, C. Cameron, and M. Stanley, IEEE Computer 38, 46 (2005).




Holographic 3D display

Meaning of ‘Data Capacity’ in 3D display

2 2

2

u v u v

D a ta c a p a c ity A r e a o f s c r e e n F ie ld o f v ie w w a v e le n g th C o lo r d e p th

N M W W

Space-Bandwidth Product

12

f

d

uM

p

Np

p

p

ap

ap

u

v

v

uW

vW

Transfer lens

Focal plane

0 order

diffraction

-1 order diffraction

on v-axis

+1 order diffraction

on v-axis

Local viewing angle

Spherical phase

resulting from

Amplitude contour

by sinc function

Pixels of SLM

d f

,c c

Central direction of

local viewing angle



Spatial Coherence and Expressible Depth

13

2ad if f

Wc

W

2

cl

0z zz

0z

e y eW

Hologram plane

Observer

If z > 0,

d iff c e y eW W W

1 .2 2

2d iff c

c

W W W za l

Spot size which can be generated from hologram with size 2a

Resolution limit of human eye

0eyeW c z z

Relation between spatial coherence and expressible depth

0 0.2 0.4 0.6 0.8 1 1.2 1.4 1.6 1.8 2-7000

-6000

-5000

-4000

-3000

-2000

-1000

0

1000

2000

0 0.2 0.4 0.6 0.8 1 1.2 1.4 1.6 1.8 2-7000

-6000

-5000

-4000

-3000

-2000

-1000

0

1000

2000

z

cl

0

1 .2 2

c a zz

c a

0z

2 1 .2 2c

al

c a

0 02 2

2 1 .2 2 2 1 .2 2

c c

c c

ca z l ca z lz

a ca l a ca l




22 2 2

l a l l a l

2 2 2

2 2

2

2 2 2

l a

l l a

Optical path length difference


l

a

0

2 2

2 2 20

2

20

2

3 20

1

2 2 2

2

2 2 2 1

2 1

2 s in 2 c o s 2

c o s 2 c o s

N d l

l l ad l

l a

a l a ld l

a l

a ad

a

2

20

1 s in

c o s

a aN d

Number of longitudinal resolvable points

Paraxial Approximation



Holographic Stereogram Stereoscopic Hologram

- Synthetic Aperture - Viewing Window

15

Division of Angular Spectrum

in Spatial Frequency Domain

Concentration of Information

on Specified Position in Real Domain




16

M. W. Halle, The Generalized Holographic Stereogram, Master Thesis, Massachusetts Institute of Technology (1991).

http://www.media.mit.edu/spi/hrdcpyimages.html

http://www.zebraimaging.com/zebra-imaging-emerging-technology/


Holographic Stereogram



17

Division of the Wigner distribution function

x

v

x

v

x

v

Synthesis at object plane Synthesis at Fourier plane Synthesis at Fresnel plane

x

v

x

v

After a Fresnel transform After a Fourier transform

x

v


The area in the Wigner distribution function is equal to the space-bandwidth product.



1.8m

20inch

10inch

View volume defined

by 4K-resolution hologram40inch

View volume defined

by 2K-resolution hologram

View volume defined

by 8K-resolution hologram

Achievable screen size according to

space-bandwidth product of SLM

18

T ra n s v e rs e re s o lu t io n a t s c re e n

0 .1 1

W id th o f v ie w in g w in d o w a t p u p il o f e ye

1 .8 8 .2 @ 0 .5V W

p m m

w m p m m m


Stereographic Hologram



19

The Wigner distribution in Stereographic holographic display

x

v

At the screen

x

v

At the viewing window




20

Projection-type holographic display

Screen size: D=203 mm

Field of view: 0.4° (estimation)

Device: 3 LCoS SLMs



VISIO20 system

Screen size: D=508 mm

Field of view: 0.18° (estimation)

Device: LCD SLM

Parallax: Vertical parallax-only


SeeReal holographic display

N. Leister, A. Schwerdtner, G. Füutterer, S. Buschbeck, J.-C. Olaya, S, Flon, Proc. SPIE 6911, 69110V (2008).

R. Haussler, A. Schwerdtner, and N. Leister, Proc. SPIE 6803, 68030M (2008).




21

Small-aperture SLM

Viewing window

Light source

Projection optics

with a pair of parabolic mirrors Hologram plane

Large-aperture SLM

Viewing windowLight source

Hologram planeHologram plane

Viewing window

Design of stereoscopic holographic display

Display with a large-aperture SLM

Projection-type display Basic geometry of stereoscopic

holographic display




Large-scale spatial light modulator

22


Position of Viewing window

l=1800mm

CCD

d=1323.5mm

d=1125mm

d=642.8mm

This hologram is generated under the

situation that ‘K’ and ‘U’ are

positioned at 0mm and ‘N’ is

positioned at1323.5mm in front of

the screen.

Computer Generated Hologram 20” Spatial light modulator

Lens

Laser module

Camera



23

Target application


Functions



24

1st group2nd group

Viewing

Window

Light

Source

Position of input

Posi

tion o

f o

utp

ut

0

20

40

60

80

100

120

-30-25-20-15-10-50

1 4 3 1 1 33 1 2 .7 9 0

4 0 3 .7 7 1o u t

in

zz

3 6 3 .8 7 1

4 0 7 .0 0 8o u t in

in

x xz

Transformation

3 6 3 .8 7 1

4 0 7 .0 0 8o u t in

in

y yz

Lens design

1 4 3 1 1 34 0 3 .7 7 1

3 1 2 .7 9 0in

o u t

zz

3 9 3 .3 0 70 .0 0 8 8 9 8

3 1 2 .7 9 0in o u t

o u t

x xz

Inverse transformation

3 9 3 .3 0 70 .0 0 8 8 9 8

3 1 2 .7 9 0in o u t

o u t

y yz




25

Assembly of lenses




26

System layout

Spatial light modulators

Input integrated optics

Motorized stages with

light sources array

Control boards

Large-format beamsplitter 2942mm

15

85

mm

913mm 630mm

Dimensions




Projection-type holographic display

Filter

27

Epson L3C07U-8x

Screen size: 0.61” diagonal

Pixel number: 1920x1080

Pixel pitch: 7.0mircometers

Amplitude modulation




Optical Reconstruction

28




29

Target application




30

System layout


Light engines

Projection mirrors

Manual stage

Design of projection optics



31

Light engine

SLMs

BS

Lasers

Mechanical

stage

Mirrors

FT lens

Filter

SLM

Controller


1,4

73

mm

610m

m660m

m

1,335mm

Dimensions



32

Broadcasting of holographic contents

V. Michael Bove, Real-time holographic video images with commodity PC hardware


Warsaw University of Technology

1 – all proc. at capture 2 – all proc. at display

3 – some processing at both sides

M. Kujawińska, T. Kozacki, Holographic television: status and future

in Optical Imaging and Metrology : Advanced Technologies (Wiley, 2012).



33


Head-mounted holographic display

Our head-mounted holographic display system

under the co-work with Prof. Hwi Kim’s lab in Korea University

Category: Stereoscopic hologram/ Spatial multiplexing/ Full-parallax

Advantage: Omission of eye-tracking function

Issue: Compact system



34


The latest Texas Instrument DMD

Data capacity=800Mb @60frames

Personal holographic display

Device

Category: Stereoscopic hologram/ Spatiotemporal multiplexing/ Full-parallax

Advantage: 8-bit gray modulation

Issue: Optically addressable SLM/ Optical design

Color=24bit

SBP= 16.7Mpixels for each viewing window

Horizontal resol.= 5,443pixels

Vertical resol.=3,062pixels

Data

assignment

Physical

dimension

Screen size= 40inch diagonal @ 2.55m

Field of view= 0.18deg.



35


The latest Texas Instrument DMD

Data capacity=800Mb @60frames

Public holographic display

Device

Category: Holographic stereogram/ Spatiotemporal multiplexing/ Horizontal parallax-only


Issue: Optically addressable SLM/ Optical design

Color=24bit

SBP= 33.3Mpixels



Data

assignment

Physical

dimension

Screen size= 5inch diagonal 111mm(H) x 62mm(V)




36


Mobile application

Data capacity=1GB

=133Mb @60frames Device

Category: Stereoscopic hologram/ Full-parallax


Issue: Device/ Optical elements

Color=24bit

SBP= 2.77Mpixels for each viewing window



Data

assignment

Physical

dimension

Screen size= 2inch diagonal @ 0.31m


Requirement of spatial coherence length

for reconstructing an object

at the position, 100mm apart from the screen

0 .4 0 9c

l m m



37

5. Summary

Digital holographic displays can be classified in several ways according to the

technologies such as modulation and multiplexing. Especially, ‘stereoscopic

hologram’ technique is one of key issues.

My group is working on five different types of holographic displays under tight

collaboration with Prof. Kim’s group in Korea University.

Some applications seem to have potential to be realized in the near future. Their

properties can be estimated based on current technologies.


Kyungpook National University - 3DOT3dot.knu.ac.kr/.../2015/05/Technologies-of-Digital... · 3DOT Technologies of Digital Holographic Display Joonku Hahn Kyungpook National University

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